44 



BULLETIN 429, U. S. DEPARTMENT OF AGRICULTURE. 



THE FIRST BROOD OF LARVE. 



Length of feeding period. — The length of the feeding period of larvae 

 of this brood covered a range of 22 days, the greatest number, 38, hav- 

 ing completed the period in 24 days. The maximum time is 38 days, 

 and the minimum period 16 days. The average period for the entire 

 212 individuals is found to be 24.45 days, which is 2.93 days greater 

 than the corresponding period for the first brood in 1912. 



Feeding period of wintering larvae. — It is generally conceded that 

 wintering larvae experience a longer feeding period than those trans- 

 forming the same season. In Table" XXXVI it is shown that of 15 

 wintering larvae of the first brood a maximum period of 31 days was 

 noted; a minimum period of 22 days, with an average period of 25.13 

 days. This is an increase of but 0.68 day over the feeding period of 

 the transforaiing larvae of this brood. 



Table XXXVI. 



-Length of feeding period of wintering codling-moth lurvse of the first 

 brood, Roswell, N. Mex., 1918. 







Date of— 





Observa- 

 tion. 















No. 



Hatch- 



Leaving 



Days 





ing. 



the fruit. 



feeding. 



1 



May 9 



June 5 



27 



2 



9 



5 



27 



3 



15 



6 



22 



4 



16 



12 



27 



5 



16 



16 



31 



6 



IS 



14 



27 



7 



27 



19 



23 



8 



28 



21 



24 



9 



28 



22 



25 



10 



28 



23 



26 



11 



28 



24 



07 



12 



29 



20 



22 



13 



June 2 



2fi 



24 



14 



4 



27 



23 



15 



4 



Julv 1 



27 



Maximum days, 31; minimum days, 22; average, 25.13; average for transforming, 24.45. 



Percentage of wintering larvx. — Of the larvae of the first brood 

 under observation 15 of the 212 proved to be wintering larvae, while 

 197 transformed the same season, showing as a result that only 7.16 

 per cent of the larvae of this brood proved to be wintering larvae. 



Larval life in the cocoon. — The larval life in the cocoon is here 

 broadly considered to be the time necessary for the making of the 

 cocoons, and is recorded as the time elapsing between the date the 

 larvae leave the fruit and the time of pupation. The wintering larvae 

 of the first brood are not included here, since these remain in the 

 larval stage until the following spring. In Table XXXVII are found 

 the results of 193 observations which show a variation of from 2 

 to 21 days, and an average period of 5.7 days. 



